A friend of mine has a newish A4 Estate All Road Automatic, and says he finds the diesel nothing like as responsive as the previous 2 litre petrol he had on an A6.
From 1500-3000 RPM, it should be at least equal to the petrol. It'll be a bit soggy at low speed, and breathless at higher RPM but in the middle, it should be, as roly says, like a rocket.
If the 2 litre petrol is the excellent TFSi 200bhp engine then by comparison the diesel will be a bit of a sluggard. Even with the diesel's mid range torque the petrol will be livelier and much more responsive.
